1
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Kang Y, Pogany J, Nagy PD. Proviral role of ATG2 autophagy related protein in tomato bushy stunt virus replication through bulk phospholipid transfer into the viral replication organelle. Mol Biol Cell 2024; 35:ar124. [PMID: 39110527 DOI: 10.1091/mbc.e24-05-0236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2024] Open
Abstract
Subversion of cellular membranes and membrane proliferation are used by positive-strand RNA viruses to build viral replication organelles (VROs) that support virus replication. The biogenesis of the membranous VROs requires major changes in lipid metabolism and lipid transfer in infected cells. In this work, we show that tomato bushy stunt virus (TBSV) hijacks Atg2 autophagy related protein with bulk lipid transfer activity into VROs via interaction with TBSV p33 replication protein. Deletion of Atg2 in yeast and knockdown of Atg2 in Nicotiana benthamiana resulted in decreased TBSV replication. We found that subversion of Atg2 by TBSV was important to enrich VRO membranes with phosphatidylethanolamine (PE), phosphatidylserine (PS) and PI(3)P phosphoinositide. Interestingly, inhibition of autophagy did not affect the efficient recruitment of Atg2 into VROs, and overexpression of Atg2 enhanced TBSV replication, indicating autophagy-independent subversion of Atg2 by TBSV. These findings suggest that the proviral function of Atg2 lipid transfer protein is in VRO membrane proliferation. In addition, we find that Atg2 interacting partner Atg9 with membrane lipid-scramblase activity is also coopted for tombusvirus replication. Altogether, the subversion of Atg2 bridge-type lipid transfer protein provides a new mechanism for tombusviruses to greatly expand VRO membranes to support robust viral replication.
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Affiliation(s)
- Yuanrong Kang
- Department of Plant Pathology, University of Kentucky, Plant Science Building, Lexington, KY 40546
| | - Judit Pogany
- Department of Plant Pathology, University of Kentucky, Plant Science Building, Lexington, KY 40546
| | - Peter D Nagy
- Department of Plant Pathology, University of Kentucky, Plant Science Building, Lexington, KY 40546
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2
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Shen Q, Yang M, Wang S, Chen X, Chen S, Zhang R, Xiong Z, Leng Y. The pivotal role of dysregulated autophagy in the progression of non-alcoholic fatty liver disease. Front Endocrinol (Lausanne) 2024; 15:1374644. [PMID: 39175576 PMCID: PMC11338765 DOI: 10.3389/fendo.2024.1374644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 07/23/2024] [Indexed: 08/24/2024] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a clinicopathologic syndrome characterized by excessive fat deposition in hepatocytes and a major cause of end-stage liver disease. Autophagy is a metabolic pathway responsible for degrading cytoplasmic products and damaged organelles, playing a pivotal role in maintaining the homeostasis and functionality of hepatocytes. Recent studies have shown that pharmacological intervention to activate or restore autophagy provides benefits for liver function recovery by promoting the clearance of lipid droplets (LDs) in hepatocytes, decreasing the production of pro-inflammatory factors, and inhibiting activated hepatic stellate cells (HSCs), thus improving liver fibrosis and slowing down the progression of NAFLD. This article summarizes the physiological process of autophagy, elucidates the close relationship between NAFLD and autophagy, and discusses the effects of drugs on autophagy and signaling pathways from the perspectives of hepatocytes, kupffer cells (KCs), and HSCs to provide assistance in the clinical management of NAFLD.
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Affiliation(s)
- Qiaohui Shen
- College of Traditional Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - Ming Yang
- College of Traditional Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
- Department of Liver, Spleen and Gastroenterology, First Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Song Wang
- Department of Liver, Spleen and Gastroenterology, First Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Xingyu Chen
- Department of Liver, Spleen and Gastroenterology, First Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Sulan Chen
- College of Traditional Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - Rui Zhang
- College of Traditional Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - Zhuang Xiong
- Department of Liver, Spleen and Gastroenterology, First Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Yan Leng
- College of Traditional Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
- Department of Liver, Spleen and Gastroenterology, First Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
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3
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Choi J, Jang H, Xuan Z, Park D. Emerging roles of ATG9/ATG9A in autophagy: implications for cell and neurobiology. Autophagy 2024:1-15. [PMID: 39099167 DOI: 10.1080/15548627.2024.2384349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 07/01/2024] [Accepted: 07/22/2024] [Indexed: 08/06/2024] Open
Abstract
Atg9, the only transmembrane protein among many autophagy-related proteins, was first identified in the year 2000 in yeast. Two homologs of Atg9, ATG9A and ATG9B, have been found in mammals. While ATG9B shows a tissue-specific expression pattern, such as in the placenta and pituitary gland, ATG9A is ubiquitously expressed. Additionally, ATG9A deficiency leads to severe defects not only at the molecular and cellular levels but also at the organismal level, suggesting key and fundamental roles for ATG9A. The subcellular localization of ATG9A on small vesicles and its functional relevance to autophagy have suggested a potential role for ATG9A in the lipid supply during autophagosome biogenesis. Nevertheless, the precise role of ATG9A in the autophagic process has remained a long-standing mystery, especially in neurons. Recent findings, however, including structural, proteomic, and biochemical analyses, have provided new insights into its function in the expansion of the phagophore membrane. In this review, we aim to understand various aspects of ATG9 (in invertebrates and plants)/ATG9A (in mammals), including its localization, trafficking, and other functions, in nonneuronal cells and neurons by comparing recent discoveries related to ATG9/ATG9A and proposing directions for future research.Abbreviation: AP-4: adaptor protein complex 4; ATG: autophagy related; cKO: conditional knockout; CLA-1: CLArinet (functional homolog of cytomatrix at the active zone proteins piccolo and fife); cryo-EM: cryogenic electron microscopy; ER: endoplasmic reticulum; KO: knockout; PAS: phagophore assembly site; PtdIns3K: class III phosphatidylinositol 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; RB1CC1/FIP200: RB1 inducible coiled-coil 1; SV: synaptic vesicle; TGN: trans-Golgi network; ULK: unc-51 like autophagy activating kinase; WIPI2: WD repeat domain, phosphoinositide interacting 2.
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Affiliation(s)
- Jiyoung Choi
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon, South Korea
- Department of Biotechnology, The Catholic University of Korea, Bucheon, South Korea
| | - Haeun Jang
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon, South Korea
| | - Zhao Xuan
- School of Biology and Ecology, University of Maine, Orono, ME, USA
| | - Daehun Park
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon, South Korea
- Department of Biotechnology, The Catholic University of Korea, Bucheon, South Korea
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4
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Horváth L, Biri-Kovács B, Baranyai Z, Stipsicz B, Méhes E, Jezsó B, Krátký M, Vinšová J, Bősze S. New Salicylanilide Derivatives and Their Peptide Conjugates as Anticancer Compounds: Synthesis, Characterization, and In Vitro Effect on Glioblastoma. ACS OMEGA 2024; 9:16927-16948. [PMID: 38645331 PMCID: PMC11024950 DOI: 10.1021/acsomega.3c05727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 12/28/2023] [Accepted: 01/03/2024] [Indexed: 04/23/2024]
Abstract
Pharmacologically active salicylanilides (2-hydroxy-N-phenylbenzamides) have been a promising area of interest in medicinal chemistry-related research for quite some time. This group of compounds has shown a wide spectrum of biological activities, including but not limited to anticancer effects. In this study, substituted salicylanilides were chosen to evaluate the in vitro activity on U87 human glioblastoma (GBM) cells. The parent salicylanilide, salicylanilide 5-chloropyrazinoates, a 4-aminosalicylic acid derivative, and the new salicylanilide 4-formylbenzoates were chemically and in vitro characterized. To enhance the internalization of the compounds, they were conjugated to delivery peptides with the formation of oxime bonds. Oligotuftsins ([TKPKG]n, n = 1-4), the ligands of neuropilin receptors, were used as GBM-targeting carrier peptides. The in vitro cellular uptake, intracellular localization, and penetration ability on tissue-mimicking models of the fluorescent peptide derivatives were determined. The compounds and their peptide conjugates significantly decreased the viability of U87 glioma cells. Salicylanilide compound-induced GBM cell death was associated with activation of autophagy, as characterized by immunodetection of autophagy-related processing of light chain 3 protein.
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Affiliation(s)
- Lilla Horváth
- ELKH-ELTE
Research Group of Peptide Chemistry, Eötvös Loránd
Research Network, Eötvös Loránd
University, Budapest 1117, Hungary
| | - Beáta Biri-Kovács
- ELKH-ELTE
Research Group of Peptide Chemistry, Eötvös Loránd
Research Network, Eötvös Loránd
University, Budapest 1117, Hungary
| | - Zsuzsa Baranyai
- ELKH-ELTE
Research Group of Peptide Chemistry, Eötvös Loránd
Research Network, Eötvös Loránd
University, Budapest 1117, Hungary
| | - Bence Stipsicz
- ELKH-ELTE
Research Group of Peptide Chemistry, Eötvös Loránd
Research Network, Eötvös Loránd
University, Budapest 1117, Hungary
- Institute
of Biology, Doctoral School of Biology, Eötvös Loránd University, Budapest 1117, Hungary
| | - Előd Méhes
- Institute
of Physics, Department of Biological Physics, Eötvös Loránd University, Budapest 1117, Hungary
| | - Bálint Jezsó
- Research
Centre for Natural Sciences, Institute of
Enzymology, Budapest 1053, Hungary
- ELTE-MTA
“Momentum” Motor Enzymology Research Group, Department
of Biochemistry, Eötvös Loránd
University, Budapest 1117, Hungary
| | - Martin Krátký
- Department
of Organic and Bioorganic Chemistry, Faculty of Pharmacy in Hradec
Králové, Charles University, 500 03 Hradec Králové, Czech Republic
| | - Jarmila Vinšová
- Department
of Organic and Bioorganic Chemistry, Faculty of Pharmacy in Hradec
Králové, Charles University, 500 03 Hradec Králové, Czech Republic
| | - Szilvia Bősze
- ELKH-ELTE
Research Group of Peptide Chemistry, Eötvös Loránd
Research Network, Eötvös Loránd
University, Budapest 1117, Hungary
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5
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Kong Y, Guo P, Xu J, Li J, Wu M, Zhang Z, Wang Y, Liu X, Yang L, Liu M, Zhang H, Wang P, Zhang Z. MoMkk1 and MoAtg1 dichotomously regulating autophagy and pathogenicity through MoAtg9 phosphorylation in Magnaporthe oryzae. mBio 2024; 15:e0334423. [PMID: 38501872 PMCID: PMC11005334 DOI: 10.1128/mbio.03344-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 02/28/2024] [Indexed: 03/20/2024] Open
Abstract
Autophagy is a central biodegradation pathway critical in eliminating intracellular cargo to maintain cellular homeostasis and improve stress resistance. At the same time, the key component of the mitogen-activated protein kinase cascade regulating cell wall integrity signaling MoMkk1 has an essential role in the autophagy of the rice blast fungus Magnaporthe oryzae. Still, the mechanism of how MoMkk1 regulates autophagy is unclear. Interestingly, we found that MoMkk1 regulates the autophagy protein MoAtg9 through phosphorylation. MoAtg9 is a transmembrane protein subjected to phosphorylation by autophagy-related protein kinase MoAtg1. Here, we provide evidence demonstrating that MoMkk1-dependent MoAtg9 phosphorylation is required for phospholipid translocation during isolation membrane stages of autophagosome formation, an autophagic process essential for the development and pathogenicity of the fungus. In contrast, MoAtg1-dependent phosphorylation of MoAtg9 negatively regulates this process, also impacting growth and pathogenicity. Our studies are the first to demonstrate that MoAtg9 is subject to MoMkk1 regulation through protein phosphorylation and that MoMkk1 and MoAtg1 dichotomously regulate autophagy to underlie the growth and pathogenicity of M. oryzae.IMPORTANCEMagnaporthe oryzae utilizes multiple signaling pathways to promote colonization of host plants. MoMkk1, a cell wall integrity signaling kinase, plays an essential role in autophagy governed by a highly conserved autophagy kinase MoAtg1-mediated pathway. How MoMkk1 regulates autophagy in coordination with MoAtg1 remains elusive. Here, we provide evidence that MoMkk1 phosphorylates MoAtg9 to positively regulate phospholipid translocation during the isolation membrane or smaller membrane structures stage of autophagosome formation. This is in contrast to the negative regulation of MoAtg9 by MoAtg1 for the same process. Intriguingly, MoMkk1-mediated MoAtg9 phosphorylation enhances the fungal infection of rice, whereas MoAtg1-dependant MoAtg9 phosphorylation significantly attenuates it. Taken together, we revealed a novel mechanism of autophagy and virulence regulation by demonstrating the dichotomous functions of MoMkk1 and MoAtg1 in the regulation of fungal autophagy and pathogenicity.
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Affiliation(s)
- Yun Kong
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Pusheng Guo
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Jiayun Xu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Jiaxu Li
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Miao Wu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Ziqi Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Yifan Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Xinyu Liu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Leiyun Yang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Muxing Liu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Haifeng Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Ping Wang
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Zhengguang Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
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6
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Ke PY. Molecular Mechanism of Autophagosome-Lysosome Fusion in Mammalian Cells. Cells 2024; 13:500. [PMID: 38534345 DOI: 10.3390/cells13060500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 03/11/2024] [Accepted: 03/12/2024] [Indexed: 03/28/2024] Open
Abstract
In eukaryotes, targeting intracellular components for lysosomal degradation by autophagy represents a catabolic process that evolutionarily regulates cellular homeostasis. The successful completion of autophagy initiates the engulfment of cytoplasmic materials within double-membrane autophagosomes and subsequent delivery to autolysosomes for degradation by acidic proteases. The formation of autolysosomes relies on the precise fusion of autophagosomes with lysosomes. In recent decades, numerous studies have provided insights into the molecular regulation of autophagosome-lysosome fusion. In this review, an overview of the molecules that function in the fusion of autophagosomes with lysosomes is provided. Moreover, the molecular mechanism underlying how these functional molecules regulate autophagosome-lysosome fusion is summarized.
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Affiliation(s)
- Po-Yuan Ke
- Department of Biochemistry & Molecular Biology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Liver Research Center, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
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7
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Wible DJ, Parikh Z, Cho EJ, Chen MD, Jeter CR, Mukhopadhyay S, Dalby KN, Varadarajan S, Bratton SB. Unexpected inhibition of the lipid kinase PIKfyve reveals an epistatic role for p38 MAPKs in endolysosomal fission and volume control. Cell Death Dis 2024; 15:80. [PMID: 38253602 PMCID: PMC10803372 DOI: 10.1038/s41419-024-06423-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 12/19/2023] [Accepted: 01/02/2024] [Indexed: 01/24/2024]
Abstract
p38 mitogen-activated protein kinases (MAPKs) participate in autophagic signaling; and previous reports suggest that pyridinyl imidazole p38 MAPK inhibitors, including SB203580 and SB202190, induce cell death in some cancer cell-types through unrestrained autophagy. Subsequent studies, however, have suggested that the associated cytoplasmic vacuolation resulted from off-target inhibition of an unidentified enzyme. Herein, we report that SB203580-induced vacuolation is rapid, reversible, and relies on the class III phosphatidylinositol 3-kinase (PIK3C3) complex and the production of phosphatidylinositol 3-phosphate [PI(3)P] but not on autophagy per se. Rather, vacuolation resulted from the accumulation of Rab7 on late endosome and lysosome (LEL) membranes, combined with an osmotic imbalance that triggered severe swelling in these organelles. Inhibition of PIKfyve, the lipid kinase that converts PI(3)P to PI(3,5)P2 on LEL membranes, produced a similar phenotype in cells; therefore, we performed in vitro kinase assays and discovered that both SB203580 and SB202190 directly inhibited recombinant PIKfyve. Cancer cells treated with either drug likewise displayed significant reductions in the endogenous levels of PI(3,5)P2. Despite these results, SB203580-induced vacuolation was not entirely due to off-target inhibition of PIKfyve, as a drug-resistant p38α mutant suppressed vacuolation; and combined genetic deletion of both p38α and p38β dramatically sensitized cells to established PIKfyve inhibitors, including YM201636 and apilimod. The rate of vacuole dissolution (i.e., LEL fission), following the removal of apilimod, was also significantly reduced in cells treated with BIRB-796, a structurally unrelated p38 MAPK inhibitor. Thus, our studies indicate that pyridinyl imidazole p38 MAPK inhibitors induce cytoplasmic vacuolation through the combined inhibition of both PIKfyve and p38 MAPKs, and more generally, that p38 MAPKs act epistatically to PIKfyve, most likely to promote LEL fission.
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Affiliation(s)
- Daric J Wible
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Zalak Parikh
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Eun Jeong Cho
- Targeted Therapeutic Drug Discovery and Development Program, Division of Chemical Biology & Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Miao-Der Chen
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Collene R Jeter
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Somshuvra Mukhopadhyay
- Division of Pharmacology & Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Kevin N Dalby
- Targeted Therapeutic Drug Discovery and Development Program, Division of Chemical Biology & Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Shankar Varadarajan
- Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3BX, UK
| | - Shawn B Bratton
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA.
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8
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Alam JM, Maruyama T, Noshiro D, Kakuta C, Kotani T, Nakatogawa H, Noda NN. Complete set of the Atg8-E1-E2-E3 conjugation machinery forms an interaction web that mediates membrane shaping. Nat Struct Mol Biol 2024; 31:170-178. [PMID: 38057553 DOI: 10.1038/s41594-023-01132-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 09/20/2023] [Indexed: 12/08/2023]
Abstract
Atg8, a ubiquitin-like protein, is conjugated with phosphatidylethanolamine (PE) via Atg7 (E1), Atg3 (E2) and Atg12-Atg5-Atg16 (E3) enzymatic cascade and mediates autophagy. However, its molecular roles in autophagosome formation are still unclear. Here we show that Saccharomyces cerevisiae Atg8-PE and E1-E2-E3 enzymes together construct a stable, mobile membrane scaffold. The complete scaffold formation induces an in-bud in prolate-shaped giant liposomes, transforming their morphology into one reminiscent of isolation membranes before sealing. In addition to their enzymatic roles in Atg8 lipidation, all three proteins contribute nonenzymatically to membrane scaffolding and shaping. Nuclear magnetic resonance analyses revealed that Atg8, E1, E2 and E3 together form an interaction web through multivalent weak interactions, where the intrinsically disordered regions in Atg3 play a central role. These data suggest that all six Atg proteins in the Atg8 conjugation machinery control membrane shaping during autophagosome formation.
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Affiliation(s)
| | | | - Daisuke Noshiro
- Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
| | - Chika Kakuta
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Tetsuya Kotani
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Hitoshi Nakatogawa
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Nobuo N Noda
- Institute of Microbial Chemistry (BIKAKEN), Tokyo, Japan.
- Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan.
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9
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Sakurai HT, Arakawa S, Yamaguchi H, Torii S, Honda S, Shimizu S. An Overview of Golgi Membrane-Associated Degradation (GOMED) and Its Detection Methods. Cells 2023; 12:2817. [PMID: 38132137 PMCID: PMC10741765 DOI: 10.3390/cells12242817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023] Open
Abstract
Autophagy is a cellular mechanism that utilizes lysosomes to degrade its own components and is performed using Atg5 and other molecules originating from the endoplasmic reticulum membrane. On the other hand, we identified an alternative type of autophagy, namely, Golgi membrane-associated degradation (GOMED), which also utilizes lysosomes to degrade its own components, but does not use Atg5 originating from the Golgi membranes. The GOMED pathway involves Ulk1, Wipi3, Rab9, and other molecules, and plays crucial roles in a wide range of biological phenomena, such as the regulation of insulin secretion and neuronal maintenance. We here describe the overview of GOMED, methods to detect autophagy and GOMED, and to distinguish GOMED from autophagy.
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Affiliation(s)
- Hajime Tajima Sakurai
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan; (H.T.S.); (S.A.); (H.Y.); (S.T.); (S.H.)
- Department of Biochemistry and Molecular Biology, Graduate School of Science, University of Hyogo, Harima Science Garden City, Himeji 678-1205, Hyogo, Japan
| | - Satoko Arakawa
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan; (H.T.S.); (S.A.); (H.Y.); (S.T.); (S.H.)
| | - Hirofumi Yamaguchi
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan; (H.T.S.); (S.A.); (H.Y.); (S.T.); (S.H.)
| | - Satoru Torii
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan; (H.T.S.); (S.A.); (H.Y.); (S.T.); (S.H.)
| | - Shinya Honda
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan; (H.T.S.); (S.A.); (H.Y.); (S.T.); (S.H.)
| | - Shigeomi Shimizu
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan; (H.T.S.); (S.A.); (H.Y.); (S.T.); (S.H.)
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10
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Feng X, Sun D, Li Y, Zhang J, Liu S, Zhang D, Zheng J, Xi Q, Liang H, Zhao W, Li Y, Xu M, He J, Liu T, Hasim A, Ma M, Xu P, Mi N. Local membrane source gathering by p62 body drives autophagosome formation. Nat Commun 2023; 14:7338. [PMID: 37957156 PMCID: PMC10643672 DOI: 10.1038/s41467-023-42829-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 10/23/2023] [Indexed: 11/15/2023] Open
Abstract
Autophagosomes are double-membrane vesicles generated intracellularly to encapsulate substrates for lysosomal degradation during autophagy. Phase separated p62 body plays pivotal roles during autophagosome formation, however, the underlying mechanisms are still not fully understood. Here we describe a spatial membrane gathering mode by which p62 body functions in autophagosome formation. Mass spectrometry-based proteomics reveals significant enrichment of vesicle trafficking components within p62 body. Combining cellular experiments and biochemical reconstitution assays, we confirm the gathering of ATG9 and ATG16L1-positive vesicles around p62 body, especially in Atg2ab DKO cells with blocked lipid transfer and vesicle fusion. Interestingly, p62 body also regulates ATG9 and ATG16L vesicle trafficking flux intracellularly. We further determine the lipid contents associated with p62 body via lipidomic profiling. Moreover, with in vitro kinase assay, we uncover the functions of p62 body as a platform to assemble ULK1 complex and invigorate PI3KC3-C1 kinase cascade for PI3P generation. Collectively, our study raises a membrane-based working model for multifaceted p62 body in controlling autophagosome biogenesis, and highlights the interplay between membraneless condensates and membrane vesicles in regulating cellular functions.
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Affiliation(s)
- Xuezhao Feng
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Daxiao Sun
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307, Dresden, Germany.
| | - Yanchang Li
- State Key Laboratory of Proteomics, National Center for Protein Sciences (Beijing), Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Beijing Proteome Research Center, Institute of Lifeomics, 102206, Beijing, China
| | - Jinpei Zhang
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Shiyu Liu
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Dachuan Zhang
- School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Jingxiang Zheng
- School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Qing Xi
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Haisha Liang
- School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Wenkang Zhao
- School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Ying Li
- School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Mengbo Xu
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Jiayu He
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Tong Liu
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Ayshamgul Hasim
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Department of Pathology, School of Basic Medicine, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Meisheng Ma
- Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ping Xu
- State Key Laboratory of Proteomics, National Center for Protein Sciences (Beijing), Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Beijing Proteome Research Center, Institute of Lifeomics, 102206, Beijing, China.
| | - Na Mi
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China.
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China.
- Key Laboratory of High Incidence Disease Research in Xinjiang (Xinjiang Medical University), Ministry of Education, Urumqi, 830011, Xinjiang, China.
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11
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Hanna M, Guillén-Samander A, De Camilli P. RBG Motif Bridge-Like Lipid Transport Proteins: Structure, Functions, and Open Questions. Annu Rev Cell Dev Biol 2023; 39:409-434. [PMID: 37406299 DOI: 10.1146/annurev-cellbio-120420-014634] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
The life of eukaryotic cells requires the transport of lipids between membranes, which are separated by the aqueous environment of the cytosol. Vesicle-mediated traffic along the secretory and endocytic pathways and lipid transfer proteins (LTPs) cooperate in this transport. Until recently, known LTPs were shown to carry one or a few lipids at a time and were thought to mediate transport by shuttle-like mechanisms. Over the last few years, a new family of LTPs has been discovered that is defined by a repeating β-groove (RBG) rod-like structure with a hydrophobic channel running along their entire length. This structure and the localization of these proteins at membrane contact sites suggest a bridge-like mechanism of lipid transport. Mutations in some of these proteins result in neurodegenerative and developmental disorders. Here we review the known properties and well-established or putative physiological roles of these proteins, and we highlight the many questions that remain open about their functions.
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Affiliation(s)
- Michael Hanna
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut, USA;
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Andrés Guillén-Samander
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut, USA;
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Pietro De Camilli
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut, USA;
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut, USA
- Aligning Science Across Parkinson's Collaborative Research Network, Chevy Chase, Maryland, USA
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12
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Suzuki M, Funakoshi T, Kumagai K, Komatsu M, Waguri S. ATG9A supports Chlamydia trachomatis infection via autophagy-independent mechanisms. Microbiol Spectr 2023; 11:e0277423. [PMID: 37707289 PMCID: PMC10580829 DOI: 10.1128/spectrum.02774-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 07/18/2023] [Indexed: 09/15/2023] Open
Abstract
Chlamydia trachomatis infection can be regulated by autophagy-related (ATG) genes. Here, we found that the depletion of ATG9A, one of the core ATG genes, in HeLa cells suppressed C. trachomatis growth in the inclusion. The growth was restored by re-expressing ATG9A or an ATG9A mutant impairing lipid scramblase activity in ATG9A-knockout (KO) cells. Moreover, the depletion of lipid transfer proteins ATG2A/B, responsible for isolation membrane expansion together with ATG9A, did not significantly alter the growth, suggesting that the non-autophagic function of ATG9A supports C. trachomatis infection. ATG9A-KO cells showed no infection-induced redistribution of the Golgi from the perinuclear region to inclusion, which was restored by re-expressing the mutant but not the ATG9A mutant lacking an N-terminal adapter protein-binding domain. Re-expression of the N-terminal deletion mutant in ATG9A-KO cells did not rescue C. trachomatis growth, suggesting the importance of this domain for its growth. Although ATG9A-KO cells showed enhanced TBK1 activation, interferon (IFN)-β was not significantly increased, excluding the possibility that upregulation of stimulator of IFN genes (STING) signaling suppressed bacterial growth. Taken together, these findings suggest that the proper trafficking, rather than the isolation membrane expansion function, of ATG9A assists C. trachomatis growth in the inclusion. IMPORTANCE ATG9A is an autophagy-related gene that functions during the isolation membrane expansion process to form autophagosomes, but it also has other functions independent of autophagy. In this study, we employed ATG9A-deficient HeLa cells and found that the absence of ATG9A negatively impacted proliferation of Chlamydia trachomatis in inclusions. Furthermore, rescue experiments using ATG9A mutants revealed that this action was mediated not by its autophagic function but by its binding ability to clathrin adapter proteins. These findings suggest that the proper trafficking of ATG9A assists C. trachomatis growth in the inclusion.
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Affiliation(s)
- Michitaka Suzuki
- Department of Anatomy and Histology, Fukushima Medical University School of Medicine, Hikarigaoka, Fukushima, Japan
| | - Tomoko Funakoshi
- Department of Physiology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Keigo Kumagai
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, Japan
| | - Masaaki Komatsu
- Department of Physiology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Satoshi Waguri
- Department of Anatomy and Histology, Fukushima Medical University School of Medicine, Hikarigaoka, Fukushima, Japan
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13
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Broadbent DG, Barnaba C, Perez GI, Schmidt JC. Quantitative analysis of autophagy reveals the role of ATG9 and ATG2 in autophagosome formation. J Cell Biol 2023; 222:e202210078. [PMID: 37115157 PMCID: PMC10148237 DOI: 10.1083/jcb.202210078] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 02/03/2023] [Accepted: 03/17/2023] [Indexed: 04/29/2023] Open
Abstract
Autophagy is a catabolic pathway required for the recycling of cytoplasmic materials. To define the mechanisms underlying autophagy it is critical to quantitatively characterize the dynamic behavior of autophagy factors in living cells. Using a panel of cell lines expressing HaloTagged autophagy factors from their endogenous loci, we analyzed the abundance, single-molecule dynamics, and autophagosome association kinetics of autophagy proteins involved in autophagosome biogenesis. We demonstrate that autophagosome formation is inefficient and ATG2-mediated tethering to donor membranes is a key commitment step in autophagosome formation. Furthermore, our observations support the model that phagophores are initiated by the accumulation of autophagy factors on mobile ATG9 vesicles, and that the ULK1 complex and PI3-kinase form a positive feedback loop required for autophagosome formation. Finally, we demonstrate that the duration of autophagosome biogenesis is ∼110 s. In total, our work provides quantitative insight into autophagosome biogenesis and establishes an experimental framework to analyze autophagy in human cells.
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Affiliation(s)
- David G. Broadbent
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
- College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Carlo Barnaba
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
| | - Gloria I. Perez
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
| | - Jens C. Schmidt
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
- Department of Obstetrics and Gynecology, Michigan State University, East Lansing, MI, USA
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14
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Olivas TJ, Wu Y, Yu S, Luan L, Choi P, Guinn ED, Nag S, De Camilli PV, Gupta K, Melia TJ. ATG9 vesicles comprise the seed membrane of mammalian autophagosomes. J Cell Biol 2023; 222:e202208088. [PMID: 37115958 PMCID: PMC10148236 DOI: 10.1083/jcb.202208088] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 03/20/2023] [Accepted: 04/05/2023] [Indexed: 04/30/2023] Open
Abstract
As the autophagosome forms, its membrane surface area expands rapidly, while its volume is kept low. Protein-mediated transfer of lipids from another organelle to the autophagosome likely drives this expansion, but as these lipids are only introduced into the cytoplasmic-facing leaflet of the organelle, full membrane growth also requires lipid scramblase activity. ATG9 harbors scramblase activity and is essential to autophagosome formation; however, whether ATG9 is integrated into mammalian autophagosomes remains unclear. Here we show that in the absence of lipid transport, ATG9 vesicles are already competent to collect proteins found on mature autophagosomes, including LC3-II. Further, we use styrene-maleic acid lipid particles to reveal the nanoscale organization of protein on LC3-II membranes; ATG9 and LC3-II are each fully integrated into expanding autophagosomes. The ratios of these two proteins at different stages of maturation demonstrate that ATG9 proteins are not continuously integrated, but rather are present on the seed vesicles only and become diluted in the expanding autophagosome membrane.
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Affiliation(s)
- Taryn J. Olivas
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
| | - Yumei Wu
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
- Department of Neuroscience, School of Medicine, Yale University, New Haven, CT, USA
- Howard Hughes Medical Institute, School of Medicine, Yale University, New Haven, CT, USA
- Program in Cellular Neuroscience Neurodegeneration and Repair, School of Medicine, Yale University, New Haven, CT, USA
| | - Shenliang Yu
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
| | - Lin Luan
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
| | - Peter Choi
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
| | - Emily D. Guinn
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
| | - Shanta Nag
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
| | - Pietro V. De Camilli
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
- Department of Neuroscience, School of Medicine, Yale University, New Haven, CT, USA
- Howard Hughes Medical Institute, School of Medicine, Yale University, New Haven, CT, USA
- Program in Cellular Neuroscience Neurodegeneration and Repair, School of Medicine, Yale University, New Haven, CT, USA
| | - Kallol Gupta
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
- Nanobiology Institute, Yale University, West Haven, CT, USA
| | - Thomas J. Melia
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
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15
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Nishimura T, Lazzeri G, Mizushima N, Covino R, Tooze SA. Unique amphipathic α helix drives membrane insertion and enzymatic activity of ATG3. SCIENCE ADVANCES 2023; 9:eadh1281. [PMID: 37352354 PMCID: PMC10289646 DOI: 10.1126/sciadv.adh1281] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 05/22/2023] [Indexed: 06/25/2023]
Abstract
Autophagosome biogenesis requires a localized perturbation of lipid membrane dynamics and a unique protein-lipid conjugate. Autophagy-related (ATG) proteins catalyze this biogenesis on cellular membranes, but the underlying molecular mechanism remains unclear. Focusing on the final step of the protein-lipid conjugation reaction, the ATG8/LC3 lipidation, we show how the membrane association of the conjugation machinery is organized and fine-tuned at the atomistic level. Amphipathic α helices in ATG3 proteins (AHATG3) have low hydrophobicity and contain less bulky residues. Molecular dynamics simulations reveal that AHATG3 regulates the dynamics and accessibility of the thioester bond of the ATG3~LC3 conjugate to lipids, enabling the covalent lipidation of LC3. Live-cell imaging shows that the transient membrane association of ATG3 with autophagic membranes is governed by the less bulky-hydrophobic feature of AHATG3. The unique properties of AHATG3 facilitate protein-lipid bilayer association, leading to the remodeling of the lipid bilayer required for the formation of autophagosomes.
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Affiliation(s)
- Taki Nishimura
- PRESTO, Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076, Japan
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
- Molecular Cell Biology of Autophagy Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Gianmarco Lazzeri
- Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, Frankfurt am Main 60438, Germany
- Goethe University, Frankfurt am Main 60438, Germany
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Roberto Covino
- Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, Frankfurt am Main 60438, Germany
- Goethe University, Frankfurt am Main 60438, Germany
| | - Sharon A. Tooze
- Molecular Cell Biology of Autophagy Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
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16
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Nguyen A, Lugarini F, David C, Hosnani P, Alagöz Ç, Friedrich A, Schlütermann D, Knotkova B, Patel A, Parfentev I, Urlaub H, Meinecke M, Stork B, Faesen AC. Metamorphic proteins at the basis of human autophagy initiation and lipid transfer. Mol Cell 2023:S1097-2765(23)00321-0. [PMID: 37209685 DOI: 10.1016/j.molcel.2023.04.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 02/23/2023] [Accepted: 04/27/2023] [Indexed: 05/22/2023]
Abstract
Autophagy is a conserved intracellular degradation pathway that generates de novo double-membrane autophagosomes to target a wide range of material for lysosomal degradation. In multicellular organisms, autophagy initiation requires the timely assembly of a contact site between the ER and the nascent autophagosome. Here, we report the in vitro reconstitution of a full-length seven-subunit human autophagy initiation supercomplex built on a core complex of ATG13-101 and ATG9. Assembly of this core complex requires the rare ability of ATG13 and ATG101 to switch between distinct folds. The slow spontaneous metamorphic conversion is rate limiting for the self-assembly of the supercomplex. The interaction of the core complex with ATG2-WIPI4 enhances tethering of membrane vesicles and accelerates lipid transfer of ATG2 by both ATG9 and ATG13-101. Our work uncovers the molecular basis of the contact site and its assembly mechanisms imposed by the metamorphosis of ATG13-101 to regulate autophagosome biogenesis in space and time.
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Affiliation(s)
- Anh Nguyen
- Max-Planck Institute for Multidisciplinary Sciences, Laboratory of Biochemistry of Signal Dynamics, Göttingen, Germany
| | - Francesca Lugarini
- Max-Planck Institute for Multidisciplinary Sciences, Laboratory of Biochemistry of Signal Dynamics, Göttingen, Germany
| | - Céline David
- Institute of Molecular Medicine I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Pouya Hosnani
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany; University Medical Centre Göttingen, Department of Cellular Biochemistry, Göttingen, Germany
| | - Çağla Alagöz
- Max-Planck Institute for Multidisciplinary Sciences, Laboratory of Biochemistry of Signal Dynamics, Göttingen, Germany
| | - Annabelle Friedrich
- Institute of Molecular Medicine I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - David Schlütermann
- Institute of Molecular Medicine I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Barbora Knotkova
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany; University Medical Centre Göttingen, Department of Cellular Biochemistry, Göttingen, Germany
| | - Anoshi Patel
- Max-Planck Institute for Multidisciplinary Sciences, Laboratory of Biochemistry of Signal Dynamics, Göttingen, Germany
| | - Iwan Parfentev
- Max-Planck Institute for Multidisciplinary Sciences, Bioanalytical Mass Spectrometry, Göttingen, Germany
| | - Henning Urlaub
- Max-Planck Institute for Multidisciplinary Sciences, Bioanalytical Mass Spectrometry, Göttingen, Germany; University Medical Centre Göttingen, Institute of Clinical Chemistry, Bioanalytics Group, Göttingen, Germany
| | - Michael Meinecke
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany; University Medical Centre Göttingen, Department of Cellular Biochemistry, Göttingen, Germany
| | - Björn Stork
- Institute of Molecular Medicine I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Alex C Faesen
- Max-Planck Institute for Multidisciplinary Sciences, Laboratory of Biochemistry of Signal Dynamics, Göttingen, Germany.
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17
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Brennan L, Costello MJ, Hejtmancik JF, Menko AS, Riazuddin SA, Shiels A, Kantorow M. Autophagy Requirements for Eye Lens Differentiation and Transparency. Cells 2023; 12:475. [PMID: 36766820 PMCID: PMC9914699 DOI: 10.3390/cells12030475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/17/2023] [Accepted: 01/25/2023] [Indexed: 02/05/2023] Open
Abstract
Recent evidence points to autophagy as an essential cellular requirement for achieving the mature structure, homeostasis, and transparency of the lens. Collective evidence from multiple laboratories using chick, mouse, primate, and human model systems provides evidence that classic autophagy structures, ranging from double-membrane autophagosomes to single-membrane autolysosomes, are found throughout the lens in both undifferentiated lens epithelial cells and maturing lens fiber cells. Recently, key autophagy signaling pathways have been identified to initiate critical steps in the lens differentiation program, including the elimination of organelles to form the core lens organelle-free zone. Other recent studies using ex vivo lens culture demonstrate that the low oxygen environment of the lens drives HIF1a-induced autophagy via upregulation of essential mitophagy components to direct the specific elimination of the mitochondria, endoplasmic reticulum, and Golgi apparatus during lens fiber cell differentiation. Pioneering studies on the structural requirements for the elimination of nuclei during lens differentiation reveal the presence of an entirely novel structure associated with degrading lens nuclei termed the nuclear excisosome. Considerable evidence also indicates that autophagy is a requirement for lens homeostasis, differentiation, and transparency, since the mutation of key autophagy proteins results in human cataract formation.
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Affiliation(s)
- Lisa Brennan
- Department of Biomedical Science, Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33460, USA
| | - M. Joseph Costello
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - J. Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - A. Sue Menko
- Department of Pathology, Anatomy and Cell Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
- Department of Ophthalmology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - S. Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Alan Shiels
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Marc Kantorow
- Department of Biomedical Science, Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33460, USA
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18
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Capitanio C, Bieber A, Wilfling F. How Membrane Contact Sites Shape the Phagophore. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2023; 6:25152564231162495. [PMID: 37366413 PMCID: PMC10243513 DOI: 10.1177/25152564231162495] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/15/2023] [Accepted: 02/18/2023] [Indexed: 06/28/2023]
Abstract
During macroautophagy, phagophores establish multiple membrane contact sites (MCSs) with other organelles that are pivotal for proper phagophore assembly and growth. In S. cerevisiae, phagophore contacts have been observed with the vacuole, the ER, and lipid droplets. In situ imaging studies have greatly advanced our understanding of the structure and function of these sites. Here, we discuss how in situ structural methods like cryo-CLEM can give unprecedented insights into MCSs, and how they help to elucidate the structural arrangements of MCSs within cells. We further summarize the current knowledge of the contact sites in autophagy, focusing on autophagosome biogenesis in the model organism S. cerevisiae.
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Affiliation(s)
- Cristina Capitanio
- Department of Molecular Machines and
Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
- Aligning Science Across Parkinson's (ASAP)
Collaborative Research Network, Chevy Chase, MD, USA
| | - Anna Bieber
- Department of Molecular Machines and
Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
- Aligning Science Across Parkinson's (ASAP)
Collaborative Research Network, Chevy Chase, MD, USA
| | - Florian Wilfling
- Mechanisms of Cellular Quality Control, Max Planck Institute of Biophysics, Frankfurt a. M., Germany
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19
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Marquardt L, Taylor M, Kramer F, Schmitt K, Braus GH, Valerius O, Thumm M. Vacuole fragmentation depends on a novel Atg18-containing retromer-complex. Autophagy 2023; 19:278-295. [PMID: 35574911 PMCID: PMC9809942 DOI: 10.1080/15548627.2022.2072656] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The yeast PROPPIN Atg18 folds as a β-propeller with two binding sites for phosphatidylinositol-3-phosphate (PtdIns3P) and PtdIns(3,5)P2 at its circumference. Membrane insertion of an amphipathic loop of Atg18 leads to membrane tubulation and fission. Atg18 has known functions at the PAS during macroautophagy, but the functional relevance of its endosomal and vacuolar pool is not well understood. Here we show in a proximity-dependent labeling approach and by co-immunoprecipitations that Atg18 interacts with Vps35, a central component of the retromer complex. The binding of Atg18 to Vps35 is competitive with the sorting nexin dimer Vps5 and Vps17. This suggests that Atg18 within the retromer can substitute for both the phosphoinositide binding and the membrane bending capabilities of these sorting nexins. Indeed, we found that Atg18-retromer is required for PtdIns(3,5)P2-dependent vacuolar fragmentation during hyperosmotic stress. The Atg18-retromer is further involved in the normal sorting of the integral membrane protein Atg9. However, PtdIns3P-dependent macroautophagy and the selective cytoplasm-to-vacuole targeting (Cvt) pathway are only partially affected by the Atg18-retromer. We expect that this is due to the plasticity of the different sorting pathways within the endovacuolar system.Abbreviations: BAR: bin/amphiphysin/Rvs; FOA: 5-fluoroorotic acid; PAS: phagophore assembly site; PROPPIN: beta-propeller that binds phosphoinositides; PtdIns3P: phosphatidylinositol-3-phosphate; PX: phox homology.
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Affiliation(s)
- Lisa Marquardt
- Institute of Cellular Biochemistry, University Medicine, Goettingen, Germany
| | - Matthew Taylor
- Institute of Cellular Biochemistry, University Medicine, Goettingen, Germany
| | - Florian Kramer
- Institute of Cellular Biochemistry, University Medicine, Goettingen, Germany
| | - Kerstin Schmitt
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Georg-August-University, Goettingen, Germany
| | - Gerhard H. Braus
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Georg-August-University, Goettingen, Germany
| | - Oliver Valerius
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Georg-August-University, Goettingen, Germany
| | - Michael Thumm
- Institute of Cellular Biochemistry, University Medicine, Goettingen, Germany,CONTACT Michael Thumm ; Institute of Cellular Biochemistry, University Medicine, Humboldtallee 23, D-37073Goettingen, Germany
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20
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Kumar S, Ruiz N. Bacterial AsmA-Like Proteins: Bridging the Gap in Intermembrane Phospholipid Transport. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2023; 6:25152564231185931. [PMID: 37455811 PMCID: PMC10345924 DOI: 10.1177/25152564231185931] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/16/2023] [Accepted: 06/16/2023] [Indexed: 07/18/2023]
Abstract
In eukaryotic cells, nonvesicular lipid transport between organelles is mediated by lipid-transfer proteins. Recently, a new class of these lipid transporters has been described to facilitate the bulk of inter-organelle lipid transport at contact sites by forming bridge-like structures with a hydrophobic groove through which lipids travel. Because their predicted structure is composed of repeating β-groove (RBG) domains, they have been named the RBG protein superfamily. Early studies on RBG proteins VPS13 and ATG2 recognized the resemblance of their predicted structures to that of the bacterial Lpt system, which transports newly synthesized lipopolysaccharides (LPS) between the inner and the outer membranes (IMs and OMs) of Gram-negative bacteria. In these didermic bacteria, the IMs and OMs are separated by an aqueous periplasmic compartment that is traversed by a bridge-like structure built with β-jelly roll domains from several Lpt proteins that provides a hydrophobic groove for LPS molecules to travel across the periplasm. Despite structural and functional similarities between RBG proteins and the Lpt system, the bacterial AsmA-like protein family has recently emerged as the likely ancestor of RBG proteins and long sought-after transporters that facilitate the transfer of phospholipids from the IM to the OM. Here, we review our current understanding of the structure and function of bacterial AsmA-like proteins, mainly focusing on recent studies that have led to the proposal that AsmA-like proteins mediate the bulk of phospholipid transfer between the IMs and OMs.
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Affiliation(s)
- Sujeet Kumar
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Natividad Ruiz
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
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21
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Peikert K, Danek A. VPS13 Forum Proceedings: XK, XK-Related and VPS13 Proteins in Membrane Lipid Dynamics. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2023; 6:25152564231156994. [PMID: 37366410 PMCID: PMC10243564 DOI: 10.1177/25152564231156994] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 01/23/2023] [Indexed: 06/28/2023]
Abstract
In 2020, the pandemic interrupted the series of biannual International Neuroacanthocytosis Meetings that brought together clinicians, scientists, and patient groups to share research into a small group of devastating genetic diseases that combine both acanthocytosis (deformed red blood cells) and neurodegeneration with movement disorders. This Meeting Report describes talks at the 5th VPS13 Forum in January 2022, one of a series of online meetings held to fill the gap. The meeting addressed the basic biology of two key proteins implicated in chorea-acanthocytosis (mutations in VPS13A) and McLeod syndrome (mutations in XK). In a remarkable confluence of ideas, the speakers described different aspects of a single functional unit that comprises of VPS13A and XK proteins working together. Conditions caused by VPS13 (A-D) gene family mutations and related genes, such as XK, previously footnote knowledge, seem to turn central for a novel disease paradigm: bulk lipid transfer disorders.
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Affiliation(s)
- Kevin Peikert
- Translational Neurodegeneration Section
“Albrecht-Kossel”, Department of Neurology, University Medical Center Rostock, University of
Rostock, Rostock, Germany
- Center for Transdisciplinary Neurosciences
Rostock (CTNR), University Medical Center Rostock, Rostock, Germany
- United Neuroscience Campus Lund-Rostock
(UNC), Rostock site, Rostock, Germany
| | - Adrian Danek
- Department of Neurology, University Hospital,
LMU Munich, Munich, Germany
- German Center for Neurodegenerative Diseases
(Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE), Research Site Munich, Munich,
Germany
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22
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Chen A, Ding WX, Ni HM. Scramblases as Regulators of Autophagy and Lipid Homeostasis: Implications for NAFLD. AUTOPHAGY REPORTS 2022; 1:143-160. [PMID: 35509327 PMCID: PMC9066413 DOI: 10.1080/27694127.2022.2055724] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Equilibration of phospholipids between the two monolayers of the lipid bilayer of cellular membranes is mediated by scramblases acting as phospholipid shuttling proteins that are critical for cellular function, particularly during inter-organelle contact. Recent work has identified several protein scramblases, including TMEM41B, VMP1 and ATG9 that are critical in autophagy. More recently, ATG9, TMEM41B, and VMP1 have also been discovered to be important regulators of cellular lipid homeostasis. In vivo mouse models involving ablation of TMEM41B in liver have shown that knockout of these proteins can lead to rapid development of non-alcoholic steatohepatitis (NASH) and systemic dyslipidemia, though this has not been explored yet with ATG9. The resulting phenotype is likely due to the combined effects of a severe lipid secretion defect caused by stalled neutral lipids export from the endoplasmic reticulum (ER) membrane bilayer coupled with increased lipogenesis. Here we briefly discuss recent exciting findings on the topic of scramblases in autophagy, their relevance to human non-alcoholic fatty liver disease (NAFLD)/NASH, as well as future directions in this research.
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Affiliation(s)
- Allen Chen
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Wen-Xing Ding
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, USA
- Department of Internal Medicine, The University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Hong-Min Ni
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, USA
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23
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Comparative Transcriptome Analysis Unravels the Response Mechanisms of Fusarium oxysporum f.sp. cubense to a Biocontrol Agent, Pseudomonas aeruginosa Gxun-2. Int J Mol Sci 2022; 23:ijms232315432. [PMID: 36499750 PMCID: PMC9735772 DOI: 10.3390/ijms232315432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 11/30/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022] Open
Abstract
Banana Fusarium wilt, which is caused by Fusarium oxysporum f.sp. cubense Tropical Race 4 (FOC TR4), is one of the most serious fungal diseases in the banana-producing regions in east Asia. Pseudomonas aeruginosa Gxun-2 could significantly inhibit the growth of FOC TR4. Strain Gxun-2 strongly inhibited the mycelial growth of FOC TR4 on dual culture plates and caused hyphal wrinkles, ruptures, and deformities on in vitro cultures. Banana seedlings under pot experiment treatment with Gxun-2 in a greenhouse resulted in an 84.21% reduction in the disease. Comparative transcriptome analysis was applied to reveal the response and resistance of FOC TR4 to Gxun-2 stress. The RNA-seq analysis of FOC TR4 during dual-culture with P. aeruginosa Gxun-2 revealed 3075 differentially expressed genes (DEGs) compared with the control. Among the genes, 1158 genes were up-regulated, and 1917 genes were down-regulated. Further analysis of gene function and the pathway of DEGs revealed that genes related to the cell membrane, cell wall formation, peroxidase, ABC transporter, and autophagy were up-regulated, while down-regulated DEGs were enriched in the sphingolipid metabolism and chitinase. These results indicated that FOC TR4 upregulates a large number of genes in order to maintain cell functions. The results of qRT-PCR conducted on a subset of 13 genes were consistent with the results of RNA-seq data. Thus, this study serves as a valuable resource regarding the mechanisms of fungal pathogen resistance to biocontrol agents.
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24
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ATG9A and ATG2A form a heteromeric complex essential for autophagosome formation. Mol Cell 2022; 82:4324-4339.e8. [PMID: 36347259 DOI: 10.1016/j.molcel.2022.10.017] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/19/2022] [Accepted: 10/13/2022] [Indexed: 11/09/2022]
Abstract
ATG9A and ATG2A are essential core members of the autophagy machinery. ATG9A is a lipid scramblase that allows equilibration of lipids across a membrane bilayer, whereas ATG2A facilitates lipid flow between tethered membranes. Although both have been functionally linked during the formation of autophagosomes, the molecular details and consequences of their interaction remain unclear. By combining data from peptide arrays, crosslinking, and hydrogen-deuterium exchange mass spectrometry together with cryoelectron microscopy, we propose a molecular model of the ATG9A-2A complex. Using this integrative structure modeling approach, we identify several interfaces mediating ATG9A-2A interaction that would allow a direct transfer of lipids from ATG2A into the lipid-binding perpendicular branch of ATG9A. Mutational analyses combined with functional activity assays demonstrate their importance for autophagy, thereby shedding light on this protein complex at the heart of autophagy.
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25
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Wenzel EM, Elfmark LA, Stenmark H, Raiborg C. ER as master regulator of membrane trafficking and organelle function. J Cell Biol 2022; 221:e202205135. [PMID: 36108241 PMCID: PMC9481738 DOI: 10.1083/jcb.202205135] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/16/2022] [Accepted: 08/22/2022] [Indexed: 12/13/2022] Open
Abstract
The endoplasmic reticulum (ER), which occupies a large portion of the cytoplasm, is the cell's main site for the biosynthesis of lipids and carbohydrate conjugates, and it is essential for folding, assembly, and biosynthetic transport of secreted proteins and integral membrane proteins. The discovery of abundant membrane contact sites (MCSs) between the ER and other membrane compartments has revealed that, in addition to its biosynthetic and secretory functions, the ER plays key roles in the regulation of organelle dynamics and functions. In this review, we will discuss how the ER regulates endosomes, lysosomes, autophagosomes, mitochondria, peroxisomes, and the Golgi apparatus via MCSs. Such regulation occurs via lipid and Ca2+ transfer and also via control of in trans dephosphorylation reactions and organelle motility, positioning, fusion, and fission. The diverse controls of other organelles via MCSs manifest the ER as master regulator of organelle biology.
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Affiliation(s)
- Eva Maria Wenzel
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Liv Anker Elfmark
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Harald Stenmark
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Camilla Raiborg
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
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26
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A partnership between the lipid scramblase XK and the lipid transfer protein VPS13A at the plasma membrane. Proc Natl Acad Sci U S A 2022; 119:e2205425119. [PMID: 35994651 PMCID: PMC9436381 DOI: 10.1073/pnas.2205425119] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chorea-acanthocytosis (ChAc) and McLeod syndrome are diseases with shared clinical manifestations caused by mutations in VPS13A and XK, respectively. Key features of these conditions are the degeneration of caudate neurons and the presence of abnormally shaped erythrocytes. XK belongs to a family of plasma membrane (PM) lipid scramblases whose action results in exposure of PtdSer at the cell surface. VPS13A is an endoplasmic reticulum (ER)-anchored lipid transfer protein with a putative role in the transport of lipids at contacts of the ER with other membranes. Recently VPS13A and XK were reported to interact by still unknown mechanisms. So far, however, there is no evidence for a colocalization of the two proteins at contacts of the ER with the PM, where XK resides, as VPS13A was shown to be localized at contacts between the ER and either mitochondria or lipid droplets. Here we show that VPS13A can also localize at ER-PM contacts via the binding of its PH domain to a cytosolic loop of XK, that such interaction is regulated by an intramolecular interaction within XK, and that both VPS13A and XK are highly expressed in the caudate neurons. Binding of the PH domain of VPS13A to XK is competitive with its binding to intracellular membranes that mediate other tethering functions of VPS13A. Our findings support a model according to which VPS13A-dependent lipid transfer between the ER and the PM is coupled to lipid scrambling within the PM. They raise the possibility that defective cell surface exposure of PtdSer may be responsible for neurodegeneration.
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27
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Zhang Z, Sun Y, Xue J, Jin D, Li X, Zhao D, Lian F, Qi W, Tong X. The critical role of dysregulated autophagy in the progression of diabetic kidney disease. Front Pharmacol 2022; 13:977410. [PMID: 36091814 PMCID: PMC9453227 DOI: 10.3389/fphar.2022.977410] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 08/04/2022] [Indexed: 11/30/2022] Open
Abstract
Diabetic kidney disease (DKD) is one of the major public health problems in society today. It is a renal complication caused by diabetes mellitus with predominantly microangiopathy and is a major cause of end-stage renal disease (ESRD). Autophagy is a metabolic pathway for the intracellular degradation of cytoplasmic products and damaged organelles and plays a vital role in maintaining homeostasis and function of the renal cells. The dysregulation of autophagy in the hyperglycaemic state of diabetes mellitus can lead to the progression of DKD, and the activation or restoration of autophagy through drugs is beneficial to the recovery of renal function. This review summarizes the physiological process of autophagy, illustrates the close link between DKD and autophagy, and discusses the effects of drugs on autophagy and the signaling pathways involved from the perspective of podocytes, renal tubular epithelial cells, and mesangial cells, in the hope that this will be useful for clinical treatment.
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Affiliation(s)
- Ziwei Zhang
- College of Traditional Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - Yuting Sun
- Department of Endocrinology, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jiaojiao Xue
- College of Traditional Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - De Jin
- Hangzhou Hospital of Traditional Chinese Medicine, Hangzhou, China
| | - Xiangyan Li
- Northeast Asia Research Institute of Traditional Chinese Medicine, Key Laboratory of Active Substances and Biological Mechanisms of Ginseng Efficacy, Ministry of Education, Jilin Provincial Key Laboratory of Biomacromolecules of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - Daqing Zhao
- Northeast Asia Research Institute of Traditional Chinese Medicine, Key Laboratory of Active Substances and Biological Mechanisms of Ginseng Efficacy, Ministry of Education, Jilin Provincial Key Laboratory of Biomacromolecules of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - Fengmei Lian
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- *Correspondence: Fengmei Lian, ; Wenxiu Qi, ; Xiaolin Tong,
| | - Wenxiu Qi
- Northeast Asia Research Institute of Traditional Chinese Medicine, Key Laboratory of Active Substances and Biological Mechanisms of Ginseng Efficacy, Ministry of Education, Jilin Provincial Key Laboratory of Biomacromolecules of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
- *Correspondence: Fengmei Lian, ; Wenxiu Qi, ; Xiaolin Tong,
| | - Xiaolin Tong
- Institute of Metabolic Diseases, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- *Correspondence: Fengmei Lian, ; Wenxiu Qi, ; Xiaolin Tong,
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28
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Majeed ST, Majeed R, Andrabi KI. Expanding the view of the molecular mechanisms of autophagy pathway. J Cell Physiol 2022; 237:3257-3277. [DOI: 10.1002/jcp.30819] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/01/2022] [Accepted: 06/07/2022] [Indexed: 01/18/2023]
Affiliation(s)
- Sheikh Tahir Majeed
- Department of Biotechnology Central University of Kashmir Ganderbal Jammu and Kashmir India
- Growth Factor Signaling Laboratory, Department of Biotechnology University of Kashmir Srinagar Jammu and Kashmir India
| | - Rabiya Majeed
- Growth Factor Signaling Laboratory, Department of Biotechnology University of Kashmir Srinagar Jammu and Kashmir India
- Department of Biochemistry University of Kashmir Srinagar Jammu and Kashmir India
| | - Khurshid I. Andrabi
- Growth Factor Signaling Laboratory, Department of Biotechnology University of Kashmir Srinagar Jammu and Kashmir India
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29
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Hanna MG, Suen PH, Wu Y, Reinisch KM, De Camilli P. SHIP164 is a chorein motif lipid transfer protein that controls endosome-Golgi membrane traffic. J Cell Biol 2022; 221:e202111018. [PMID: 35499567 PMCID: PMC9067936 DOI: 10.1083/jcb.202111018] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 03/07/2022] [Accepted: 04/08/2022] [Indexed: 02/03/2023] Open
Abstract
Cellular membranes differ in protein and lipid composition as well as in the protein-lipid ratio. Thus, progression of membranous organelles along traffic routes requires mechanisms to control bilayer lipid chemistry and their abundance relative to proteins. The recent structural and functional characterization of VPS13-family proteins has suggested a mechanism through which lipids can be transferred in bulk from one membrane to another at membrane contact sites, and thus independently of vesicular traffic. Here, we show that SHIP164 (UHRF1BP1L) shares structural and lipid transfer properties with these proteins and is localized on a subpopulation of vesicle clusters in the early endocytic pathway whose membrane cargo includes the cation-independent mannose-6-phosphate receptor (MPR). Loss of SHIP164 disrupts retrograde traffic of these organelles to the Golgi complex. Our findings raise the possibility that bulk transfer of lipids to endocytic membranes may play a role in their traffic.
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Affiliation(s)
- Michael G. Hanna
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| | - Patreece H. Suen
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Yumei Wu
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| | - Karin M. Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD
| | - Pietro De Camilli
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
- Kavli Institue for Neuroscience, Yale University School of Medicine, New Haven, CT
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD
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30
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Larocque G, Royle SJ. Integrating intracellular nanovesicles into integrin trafficking pathways and beyond. Cell Mol Life Sci 2022; 79:335. [PMID: 35657500 PMCID: PMC9166830 DOI: 10.1007/s00018-022-04371-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 04/28/2022] [Accepted: 05/11/2022] [Indexed: 12/24/2022]
Abstract
Membrane traffic controls the movement of proteins and lipids from one cellular compartment to another using a system of transport vesicles. Intracellular nanovesicles (INVs) are a newly described class of transport vesicles. These vesicles are small, carry diverse cargo, and are involved in multiple trafficking steps including anterograde traffic and endosomal recycling. An example of a biological process that they control is cell migration and invasion, due to their role in integrin recycling. In this review, we describe what is known so far about these vesicles. We discuss how INVs may integrate into established membrane trafficking pathways using integrin recycling as an example. We speculate where in the cell INVs have the potential to operate and we identify key questions for future investigation.
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Affiliation(s)
| | - Stephen J Royle
- Centre for Mechanochemical Cell Biology, Warwick Medical School, Gibbet Hill Road, Coventry, CV4 7AL, UK.
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31
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Xu C, Fan J. Links between autophagy and lipid droplet dynamics. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2848-2858. [PMID: 35560198 DOI: 10.1093/jxb/erac003] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 01/06/2022] [Indexed: 06/15/2023]
Abstract
Autophagy is a catabolic process in which cytoplasmic components are delivered to vacuoles or lysosomes for degradation and nutrient recycling. Autophagy-mediated degradation of membrane lipids provides a source of fatty acids for the synthesis of energy-rich, storage lipid esters such as triacylglycerol (TAG). In eukaryotes, storage lipids are packaged into dynamic subcellular organelles, lipid droplets. In times of energy scarcity, lipid droplets can be degraded via autophagy in a process termed lipophagy to release fatty acids for energy production via fatty acid β-oxidation. On the other hand, emerging evidence suggests that lipid droplets are required for the efficient execution of autophagic processes. Here, we review recent advances in our understanding of metabolic interactions between autophagy and TAG storage, and discuss mechanisms of lipophagy. Free fatty acids are cytotoxic due to their detergent-like properties and their incorporation into lipid intermediates that are toxic at high levels. Thus, we also discuss how cells manage lipotoxic stresses during autophagy-mediated mobilization of fatty acids from lipid droplets and organellar membranes for energy generation.
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Affiliation(s)
- Changcheng Xu
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Jilian Fan
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
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32
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Genetic disorders of cellular trafficking. Trends Genet 2022; 38:724-751. [DOI: 10.1016/j.tig.2022.02.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 02/11/2022] [Accepted: 02/28/2022] [Indexed: 02/06/2023]
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33
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Hama Y, Morishita H, Mizushima N. Regulation of ER-derived membrane dynamics by the DedA domain-containing proteins VMP1 and TMEM41B. EMBO Rep 2022; 23:e53894. [PMID: 35044051 PMCID: PMC8811646 DOI: 10.15252/embr.202153894] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 11/30/2021] [Accepted: 12/23/2021] [Indexed: 02/05/2023] Open
Abstract
The endoplasmic reticulum (ER) is a central hub for the biogenesis of various organelles and lipid-containing structures. Recent studies suggest that vacuole membrane protein 1 (VMP1) and transmembrane protein 41B (TMEM41B), multispanning ER membrane proteins, regulate the formation of many of these ER-derived structures, including autophagosomes, lipid droplets, lipoproteins, and double-membrane structures for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication. VMP1 and TMEM41B possess a DedA domain that is widely distributed not only in eukaryotes but also in prokaryotes and predicted to adopt a characteristic structure containing two reentrant loops. Furthermore, recent studies show that both proteins have lipid scrambling activity. Based on these findings, the potential roles of VMP1 and TMEM41B in the dynamic remodeling of ER membranes and the biogenesis of ER-derived structures are discussed.
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Affiliation(s)
- Yutaro Hama
- Department of Biochemistry and Molecular BiologyGraduate School of MedicineThe University of TokyoTokyoJapan
| | - Hideaki Morishita
- Department of Biochemistry and Molecular BiologyGraduate School of MedicineThe University of TokyoTokyoJapan
- Department of PhysiologyGraduate School of MedicineJuntendo UniversityTokyoJapan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular BiologyGraduate School of MedicineThe University of TokyoTokyoJapan
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Levine TP. Sequence Analysis and Structural Predictions of Lipid Transfer Bridges in the Repeating Beta Groove (RBG) Superfamily Reveal Past and Present Domain Variations Affecting Form, Function and Interactions of VPS13, ATG2, SHIP164, Hobbit and Tweek. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2022; 5:251525642211343. [PMID: 36571082 PMCID: PMC7613979 DOI: 10.1177/25152564221134328] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Lipid transfer between organelles requires proteins that shield the hydrophobic portions of lipids as they cross the cytoplasm. In the last decade a new structural form of lipid transfer protein (LTP) has been found: long hydrophobic grooves made of beta-sheet that bridge between organelles at membrane contact sites. Eukaryotes have five families of bridge-like LTPs: VPS13, ATG2, SHIP164, Hobbit and Tweek. These are unified into a single superfamily through their bridges being composed of just one domain, called the repeating beta groove (RBG) domain, which builds into rod shaped multimers with a hydrophobic-lined groove and hydrophilic exterior. Here, sequences and predicted structures of the RBG superfamily were analyzed in depth. Phylogenetics showed that the last eukaryotic common ancestor contained all five RBG proteins, with duplicated VPS13s. The current set of long RBG protein appears to have arisen in even earlier ancestors from shorter forms with 4 RBG domains. The extreme ends of most RBG proteins have amphipathic helices that might be an adaptation for direct or indirect bilayer interaction, although this has yet to be tested. The one exception to this is the C-terminus of SHIP164, which instead has a coiled-coil. Finally, the exterior surfaces of the RBG bridges are shown to have conserved residues along most of their length, indicating sites for partner interactions almost all of which are unknown. These findings can inform future cell biological and biochemical experiments.
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Abstract
Rapid flip-flop of phospholipids across the two leaflets of biological membranes is crucial for many aspects of cellular life. The transport proteins that facilitate this process are classified as pump-like flippases and floppases and channel-like scramblases. Unexpectedly, Class A G protein-coupled receptors (GPCRs), a large class of signaling proteins exemplified by the visual receptor rhodopsin and its apoprotein opsin, are constitutively active as scramblases in vitro. In liposomes, opsin scrambles lipids at a unitary rate of >100,000 per second. Atomistic molecular dynamics simulations of opsin in a lipid membrane reveal conformational transitions that expose a polar groove between transmembrane helices 6 and 7. This groove enables transbilayer lipid movement, conceptualized as the swiping of a credit card (lipid) through a card reader (GPCR). Conformational changes that facilitate scrambling are distinct from those associated with GPCR signaling. In this review, we discuss the physiological significance of GPCR scramblase activity and the modes of its regulation in cells. Expected final online publication date for the Annual Review of Biophysics, Volume 51 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- George Khelashvili
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York, USA; .,Institute of Computational Biomedicine, Weill Cornell Medical College, New York, New York, USA
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, New York, New York, USA;
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Ashlin TG, Blunsom NJ, Cockcroft S. Courier service for phosphatidylinositol: PITPs deliver on demand. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158985. [PMID: 34111527 PMCID: PMC8266687 DOI: 10.1016/j.bbalip.2021.158985] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/18/2021] [Accepted: 06/01/2021] [Indexed: 12/30/2022]
Abstract
Phosphatidylinositol is the parent lipid for the synthesis of seven phosphorylated inositol lipids and each of them play specific roles in numerous processes including receptor-mediated signalling, actin cytoskeleton dynamics and membrane trafficking. PI synthesis is localised to the endoplasmic reticulum (ER) whilst its phosphorylated derivatives are found in other organelles where the lipid kinases also reside. Phosphorylation of PI to phosphatidylinositol (4,5) bisphosphate (PI(4,5)P2) at the plasma membrane and to phosphatidylinositol 4-phosphate (PI4P) at the Golgi are key events in lipid signalling and Golgi function respectively. Here we review a family of proteins, phosphatidylinositol transfer proteins (PITPs), that can mobilise PI from the ER to provide the substrate to the resident kinases for phosphorylation. Recent studies identify specific and overlapping functions for the three soluble PITPs (PITPα, PITPβ and PITPNC1) in phospholipase C signalling, neuronal function, membrane trafficking, viral replication and in cancer metastases.
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Affiliation(s)
- Tim G Ashlin
- Dept. of Neuroscience, Physiology and Pharmacology, Division of Biosciences, University College London, London WC1E 6JJ, UK
| | - Nicholas J Blunsom
- Dept. of Neuroscience, Physiology and Pharmacology, Division of Biosciences, University College London, London WC1E 6JJ, UK
| | - Shamshad Cockcroft
- Dept. of Neuroscience, Physiology and Pharmacology, Division of Biosciences, University College London, London WC1E 6JJ, UK.
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